The minimum time period of a salam transaction in the Hanafi mazhab

Q: I had learnt in madrasah that among the conditions for the permissibility of a salam transaction is that the period of time from the date of the sale until the date of delivery should be a minimum of one month. If the salam period is less than one month, then the transaction will not be permissible and will not be valid. 

However, I was recently informed that there is another opinion in the Hanafi Mazhab, that even if the the period of time from the date of the sale until the date of delivery is less than one month, the salam transaction will be permissible provided that there is an urf of that nature in the place where one is staying. Is this the correct view in the Hanafi Mazhab?

Being forced to take out insurance when buying a car on installments

Q: There is car company and they are selling their cars in the following manner: 

I pay a certain amount of the total and they give me the car but they don't transfer the car to my name. Then, after I pay the 9 installments, the car will come into my name. In the meanwhile, they ask me to take an insurance policy for 9 months to cover me from all risks in case something happens to the car. Is this type of deal correct?

Forcing an heir to sell their share of the inheritance

Q: There is a dispute which is currently taking place between some family members regarding a certain property which is part of the estate of their great grandfather. 

One female is part of the present heirs and is receiving a share of the property. However, one family member who is also an heir wants to buy her share against her will and take her share for his own benefit. Is this permissible?

Avoiding the sin of gheebat

Q: If ones family member backbites another to express their frustrations with their behaviour, and does it constantly, what should they do? 

Telling them to stop breaks the ties of trust and closeness, and listening to it incurs sin. What should I do? 

If one makes tawbah, will they still lose their deeds on Qiyamah?